


Monstrous

by enkelimagnus



Category: Shadowhunters (TV)
Genre: Canon-Typical Violence, F/M, Fights, Hurt/Comfort, Jonathan is still wearing Sebastian's face so he's referred to as Sebastian, Mentions of Blood, Self-Harm, light blood kink, predatory behavior, this is part of the 'Sebastian gave himself in to the Clave in like early 2B'
Language: English
Status: Completed
Published: 2020-03-23
Updated: 2020-03-23
Packaged: 2021-03-01 05:13:58
Rating: Mature
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,010
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/23279938
Author URL: https://archiveofourown.org/users/enkelimagnus/pseuds/enkelimagnus
Summary: Sebastian and Isabelle have a fight after he hurts someone for her, and it sends Sebastian in a terrible spiral.
Relationships: Isabelle Lightwood/Jonathan Christopher Morgenstern | Sebastian Verlac
Comments: 6
Kudos: 19





	Monstrous

**Author's Note:**

  * For [Miss_Shiva_Adler](https://archiveofourown.org/users/Miss_Shiva_Adler/gifts).



> This was written for the amazing Miss_Shiva_Adler, my fellow Jonabelle shipmate! This was looked over by the wonderful Em too!
> 
> I hope you enjoy this!
> 
> Please heed the tags and feel free to warn me if I should tag anything else!

Sebastian’s fingers were red with blood and he couldn’t stop staring at them. They were steady, not shaking or trembling as they should be after what he’d done. He barely even felt remorse.

He’d seen the man’s eyes follow Isabelle as she walked through the Institute. He’d seen the way he sneered at her orders, the way he shared looks with his colleagues and friends as she spoke. He’d seen the hunger in his gaze, he’d smelled the disgusting arousal the man felt when he caught her training. 

He’d been doing that for  _ weeks _ . Following her as she worked, staring at her like a predator. Sebastian hadn’t been able to take it.

He knew enough about lust as a weapon to know the man was dangerous. And he needed to be stopped. If it wasn’t Isabelle, it would be someone else. It was never one girl. It was always several, it was always monstrous.

He remembered Lilith’s lessons on lust and sex and love and how twisted it could be. Sebastian himself still had issues with his own lust and his own ways of showing love. They tended to be bloody, violent and not very… desired by the person he loved.

His fingers were red with blood and he pushed back the urge to lick them clean, to savor the kill. Even if there was no real kill to savor.

They’d stopped him before he could kill the man. Too fucking bad. The anger rose in him again, burning his veins. He could almost feel his eyes shifting to black, his power rising with the anger. 

It was so hard to control sometimes. Often, he wished he could control it. And sometimes, he wished he didn’t have to. He wished the Clave would let him explode. He wished the Lightwoods would let him explode. 

He stared at his fingers. He hadn’t been this violent in months. He hated and loved how good it felt to be mad and to be powerful.

He remembered the pale skin of the man, his face getting whiter even, his body stinking of fear. Sebastian took a deep, calming breath. The air didn’t smell like any particular emotion right now. Good. 

Heels resounded in the corridor behind the door. His senses were heightened by his activated demon blood. He felt high on it, on the blood and the fear and the feeling of power that had come with grabbing the man by the throat and ripping his junk off. 

Before Isabelle, before his new life, he would seek out a partner and fuck until the high wore off. He’d have broken them, or let them break him, depending on what he felt like. Sometimes even both in turn. 

It was different now. Isabelle wouldn’t want to have sex with him after what he’d just done. He’d seen the look on her face, the one that made him shiver and the one that meant he’d fucked up really bad. He hated to upset her. 

She took a deep breath behind the door and the key turned in the lock. The great wooden door opened and she stepped towards him. He couldn’t resist the urge to turn around and look at her.

There was blood on her tight black dress. He couldn’t see it but he could  _ smell  _ it. A shiver ran down his spine and he kept his eyes on her. Her dark hair, her tan skin, strong legs that he wanted around his waist and… 

“Stop,” Isabelle ordered. 

She knew what he was thinking. Sebastian winced. He probably had the same look in his eyes as the man had. Should he be ripping his own eyes out for that?

“Why, in the Angel’s name, did you do that?” She said, her voice harsh and cold. “Why did you think this was a good idea?”

Sebastian huffed. “He was staring at you. He was a predator.”

Isabelle crossed her arms. “I don’t fucking care. I don’t fucking care what you think you saw in him. You crossed a line!”

Sebastian couldn’t help but glare at her. “I protected you. I thought you’d be happy.” 

Her nails dug into her arms and Sebastian tried not to focus on it. He tried to rein in the snarling beast in his mind. Was this what werewolves felt like? 

“Happy?!” Isabelle exclaimed. She was so mad he could  _ smell  _ it. Fuck, it was intense. It hit Sebastian like a truck, the blood and the anger making him feel almost dizzy. “You maimed someone, almost killed the man, and now the Clave wants to put you on trial!”

Sebastian grinded his teeth. He didn’t give a fuck about the Clave. He wanted to be free, right now. He was high on blood and demonic energy and he couldn’t think of anything but riding that high. 

“I don’t care,” he replied. “The Clave can do whatever they want. I was right. And you know that.” 

Isabelle huffed. “That’s not the point. He didn’t do anything! You attacked him and almost killed him. That was wrong.”

Sebastian looked back down at his fingers. The blood was almost dry now, darker than before, stuck to his skin. He hadn’t felt this in months. 

“I protected you,” he repeated. “That’s all that matters to me, Isabelle.” 

He stood up finally from where he was sitting. Two steps below her, he was the same height as her, staring right into her eyes. 

“I don’t need your fucking protection,” Isabelle hissed. “I’m not a fucking damsel in distress and I don’t  _ want  _ your protection. Not when you act like a monster.”

Sebastian opened his mouth and closed it again. He knew it was heranger speaking but… Isabelle had been the one person to never call him a monster. The pain of that cut through the haze of the blood high like an ice cold dagger. 

He took a step closer to her, reaching to gently touch her arm, to apologize, but he couldn’t. She flinched away from him. Isabelle had realized what she’d said, but she didn’t apologize then. She looked at him with dark, angry eyes. Eyes that said, ‘I want to hurt you’. 

“I see,” he replied, colder, pained.

She just looked at him. “You’re being confined to your apartment until they question you and put you on trial,” she added. “You should go now.” 

Sebastian looked down at his hands. He felt the urge to scrub all of the blood off, to wash it all away. Isabelle walked away and the door snapped shut behind her. He stayed outside of the Institute, shoulders heavy, his entire body shaking. 

Eventually, he turned away from the Institute and walked through the wards. He pushed his hands into his pockets, so if there were people with the Sight around, they wouldn’t see the blood. 

The apartment wasn’t far, unfortunately. 

The main room was quiet, as if the apartment knew what he’d done, what he’d said. He peeled off his clothes on the way to the bathroom, sweater and jeans hitting the floor on the way. The water wasn’t set to the hottest setting. Isabelle had been the last to take a shower here.

He pushed it to the hottest for himself and stood under the water until his skin hurt and his legs ached from standing too long. He stood there until he felt the burning, until he felt it cleanse the monster out of him.

Isabelle hated it when he burnt himself like this, she said it wasn’t good. But he didn’t know any other way to make it right.

It burnt brighter and brighter until he felt like blisters were forming over his skin, yet he didn’t move. He deserved it after what he’d done.

“Sebastian?” Her voice called out from the front door. 

He didn’t answer. He didn’t know if he could. The pain was blinding him. Overwhelming him. Suffocating him. 

She must have heard the shower running and guessed what he was doing. She was going to be so bloody mad at him. His nails scraped at his already abused skin, hard enough to draw blood. He couldn’t stop himself. 

The door of the bathroom banged open. He could barely see anything, in between the water that burnt his eyes and the steam in the bathroom. He could see the general shape of her, beautiful and perfect, like an angelic apparition. She waded through the steam and he heard her pained cry.

“Sebastian!” She shouted, running into the shower. Her mouth pressed in a thin line as the burning water hit her skin and she turned off the spray. 

Unable to hold himself for much longer, dizzy with the loss of the constant burning water, Sebastian stumbled down. 

She grabbed at him, pulling him closer. Her hands slipped on his wet and painful skin, making him wince. It hurt. Everything hurt. He rested against her, soaking her dress. His face settled against her collarbone, nose against the soft skin of her throat. He breathed in as much as he could, coughing from the pain immediately after. She smelled like worry. Like love too. He wanted to cry.

She moved, grabbing her stele and reaching over to his thigh. She activated his iratze, the black rune shining golden as it healed. 

Immediately, he could breathe a little better. 

“I’m so sorry,” he croaked. “I’m so sorry, Isabelle, I’m so sorry.” 

Isabelle shushed him, keeping him close and rocking him gently. He curled into himself, into her. His body was bigger than hers, longer for sure, but he felt so small. Isabelle’s hand caressed his wet hair, rubbing patterns soothingly onto his scalp. 

The pain and the hotness left his body and soon enough, he was cold and shaking. 

With one arm around his waist, Isabelle pulled him to his feet and helped dry him with the fluffy lavender-colored towel Sebastian loved. 

He put on some comfortable clothing, sweatpants and a sweater and sat on the bed as she did the same. Her dress was soaked along with her tights and her underwear. She put on a large tshirt and some pyjama shorts, put her hair up in a bun and sat next to him. 

Her hands were soothing on him. 

Sebastian took a deep breath and reached over to touch her. She didn’t flinch away and relief and gratitude flooded him again. 

“I won’t do it again,” he whispered. “I’m sorry…”

Isabelle sighed heavily. “I didn’t mean what I said,” she replied. “I’m so sorry. I love you so much, I just…” 

Sebastian closed his eyes for a second. “I crossed a line. I know I did.” He felt so exhausted right now. 

Isabelle nodded. “I won’t say that ever again. I don’t see you as a monster, Sebastian,” she promised. 

“I know.” 

And he truly did. He knew she didn’t see him the way the others did, she never had. Still, it had hurt more than everything else he’d been through lately. She’d crushed him, for a moment. Enough so the high dissipated and the pain took over.

“I’ll do better. I’ll control myself better,” he promised in return. “I… I’m sorry I don’t feel remorse. I still think he deserved it.”

Isabelle sighed heavily. “Maybe he did. Let’s hope the Clave will see it that way. I can’t lose you. Not when I’ve just found you.” 

Sebastian took her hand in his and pulled it up to his lips. He pressed a kiss there, reverent, penitent, too. When he looked back up at her, she was smiling a little. 

Underneath the tender smile, she looked sad, worried. He should be, too. The Clave didn’t like him and he wouldn’t bear to be taken from her side. 

They both laid down on the bed and he shifted closer to her. She wrapped her arms around him and he rested his head against her chest, seeking comfort. Isabelle sighed, content. Sebastian closed his eyes, enjoying her perfume and her warmth surrounding him. 

There was nothing that made him relax like her arms around him.


End file.
